Search results for "Organosulfur compounds"
showing 10 items of 10 documents
Metabolic and process engineering for biodesulfurization in Gram-negative bacteria
2017
32 p.-2 fig.-1 tab.
Evaluation of aging processes of petroleum asphalt cements by solid state electrochemical monitoring
2018
Abstract The changes in the chemistry of organosulfur compounds from asphalt cements during aging are studied using solid state voltammetry of immobilized microparticles. Five Brazilian asphalt cements were evaluated after three forced aging processes: Rolling Thin Film Oven Test (RTFOT), Pressure Aging Vessel (PAV) and SUNTEST. It was possible to identify the presence of thiophenes, sulfides and sulfoxides in the different samples and the reactional changes during the aging processes were proposed. Voltammetric data, supported by ATR-FTIR spectroscopy, indicate that aging asphalts involve the increase of the proportion of sulfoxide and thiophene components and that polythiophene compounds …
Bioavailability and food production of organosulfur compounds from edible Allium species
2019
Abstract Allium members are known for their wide use in culinary dishes and the content of their bioactive compounds. In this aspect, edible Allium members, such as garlic (A. sativum), onion (A. cepa), leeks (A. porrum), chives (A. schoenoprasum), and shallots (A. ascalonicum), have been widely studied with respect to their functional properties in vivo. Their beneficial effects on humans are closely associated with bioavailability of organosulfur compounds (OSCs) in allyl and methyl forms. However, the OSCs are thermally unstable, so it is important to identify critical processing types/parameters that have destructive effects on bioavailability of the OSCs, and possibly to avoid them in …
Programmed Formation of HCN Oligomers through Organosulfur Catalysis
2021
An efficient, inexpensive, and reliable synthesis of diaminomaleonitrile (DAMN, 1) is described starting from readily available acetone cyanohydrin as the source of hydrogen cyanide (HCN). Diaminomaleonitrile (DAMN) is known to be an important intermediate in heterocyclic and medicinal chemistry as well as being a possible precursor for the origin of life's hypothesis within prebiotic chemistry. The mechanism of its formation through organosulfur catalysis has been investigated by electrospray ionization mass spectrometry (ESI-MS) using two newly synthesized cationic "marker" molecules as a tool that allows for sensitive detection. As a result, the proposed mechanism of a thiocyanate-mediat…
Polythiophenes as markers of asphalt and archaeological tar pitch aging. Characterization using solid-state electrochemistry
2018
The voltammetry of immobilized microparticles (VIMP) was used to characterize organosulfur components from ovens found at the Spanish archaeological sites of Cueva de Nerja (ca. 35,000cal BC), la Illeta dels Banyets (4th century BCE) and Gestalgar (12th–13th CE), and asphalt probes subjected to PAV and SUNTEST aging protocols. The voltammetric responses of the archaeological samples and the asphalt probes after photodegradation were quite similar, indicating the presence of polythiophene components which could act as age/degradation markers. Keywords: Voltammetry, Archaeology, Asphalt, Tar pitch, Organosulfur compounds
Stability and extraction of bioactive sulfur compounds from Allium genus processed by traditional and innovative technologies
2017
Abstract Since ancient times, species from the Allium genus have been used in both culinary and medicinal applications. The health promoting properties, with well documented “evidence-based” studies, were attributed to the genus’ high content of bioactive organosulfur compounds. For these reasons, the organosulfur compounds have attracted interest in both food and pharmaceutical industries to be used as additives or supplements. Therefore, improvement in the extraction and stability during processing and storage of these molecules is crucial. The presented review documents the effects of traditional and innovative processing techniques on the extraction and stability of organosulfur compoun…
Solid state electrochemical behavior of organosulfur compounds
2017
Abstract The solid-sate electrochemistry of organosulfur compounds existing in petroleum and its derived matrices is described using the voltammetry of immobilized microparticles methodology. Cyclic and square wave voltammogrammetric responses of sulfur compounds responsible of aging of asphalt pavements, namely, thiophenes, disulfides, sulfides, sulfoxides and sulfones were determined at compound-modified graphite electrodes in contact with 0.10 M H2SO4. The electrochemical oxidation/reduction products were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy with energy dispersion x-ray detection (SEM-EDX) couple…
Environmentally relevant precursors of carbonyl sulfide in aquatic systems
1997
Seawater solutions of environmentally relevant organosulfur compounds, commercial humic acid (HA), and natural dissolved organic matter (DOM) were incubated with and without UV light in order to determine the carbonyl sulfide (COS) producing capabilities of these compounds. COS dark- and photo-production rate constants were determined for dilute solutions of the organosulfur compounds (μmol l−1) and HA/DOM (mg l−1). Dissolved COS was determined using a purge and cryogenic trap method followed by GC/FPD detection. COS was produced in considerable amounts both non-photochemically and photochemically from the reduced form of free acid of glutathione (GSH) and photochemically from cysteine (CYS…
Reversible Solvent‐Exchange‐Driven Transformations in Multifunctional Coordination Polymers Based on Copper‐Containing Organosulfur Ligands
2014
The preparation by simple direct synthesis of a series of coordination polymers based on copper with chloride or bromide and dipyrimidinedisulfide is reported. The structural characterisations of these compounds reveal a rich structural variety as a result of the number of coordination modes available to the organosulfur ligand, in combination with the bridging capabilities of the halides. Interestingly, some of the polymers displayed fully reversible solvent exchange/removal crystal-to-crystal 2D to 0D and 2D to 2D transformations. These materials show multifunctional electronic properties. Thus, some of them are semiconductors and present weak antiferromagnetic interactions, and the CuI/C…
An overview of organosulfur compounds from Allium spp.: From processing and preservation to evaluation of their bioavailability, antimicrobial, and a…
2019
The use of Allium species and their extracts has been known since immemorial times due to their health beneficial properties. It is known that functional properties of Allium genus come from the high content of bioactive compounds. The biological activity of Allium extracts will be conditioned by the type of Allium variety, agricultural conditions, and specific extraction process used since all these factors affect the content and the profile of bioactive compounds. Innovative extraction techniques in comparison to conventional processes could be considered as a promising tool to recover bioactive compounds from Allium spp. with antimicrobial and anti-inflammatory properties. Trying to fill…